A unit made from a magnetic valve and a passive valve for limiting pressure in a tank is known from DE 10 2007 025 048 A1. In a passive valve, the opening or closing is accomplished only by the pressures that are created by the fluids and applied to the sealing device. A magnetic valve, on the other hand, is a so-called active valve that is opened or closed by an electromagnetic device by a sealing device or a sealing body being actively moved. In the case of a magnetic valve, currents are conducted through a coil in order to create a magnetic field, the magnetic force of which actively moves an armature element. The movement of the armature element is used to actively move a sealing device in such a manner that a sealing seat is opened or closed in order to permit or prevent a fluidic flow.
The passive valve known from DE 10 2007 025 048 A1 has two bodies that can be moved jointly and relative to one another, through whose fluid- or pressure-controlled movement overpressures as well as underpressures in a tank can be eliminated if certain pressure limits are exceeded. The magnetic valve assigned to the passive valve actively regulates the tank pressure within the pressure limits that are allowed by the passive valve.
The passive valve and the magnetic valve have one sealing seat each. Each sealing seat represents a potential leak source so that special care is needed in the choice of seal material. There is a need for as compact and tightly sealed a valve as possible.
The sealing seat of a magnetic valve can be closed or opened via an electromagnetic device. The manner of operation of an electromagnet is generally known and is described in DE 10 2015 111 561 A1, for example, based on a low-noise sealing of a sealing seat against a spring force. There it is taught to design the magnetic force on an armature element to increase overall, so that the latter can execute a stroke against a spring force. It is further taught to continuously increase the current supply of a coil, meaning the conduction of a current through the coil of the electromagnetic device, during the movement of the armature element from an initial position into the end position. The valve is closed in the end position. Relatively high current strengths can be combined with an increased energy usage with this technique.
There is a need for a valve whose current supply is accomplished in as effective, yet low-noise a manner as possible.
It is therefore desirable to reduce over- and underpressures, in particular with a valve that can be operated actively and passively, as effectively and reliably as possible, but also in as low-noise a manner as possible.